Switch back to the regular alpha blending

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Sky/AtmosphericScattering/AtmosphericScattering.hlsl

         return float4(0.0, 0.0, 0.0, 0.0);
     }
 
-    return float4(fogColor * fogFactor, fogFactor); // Premultiplied alpha
+    return float4(fogColor, fogFactor); // Premultiplied alpha
 }
 
 

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Sky/OpaqueAtmosphericScattering.shader

             Cull   Off
             ZTest  Always
             ZWrite Off
-            Blend  One OneMinusSrcAlpha // Premultiplied Alpha
+            Blend  SrcAlpha OneMinusSrcAlpha
 
             HLSLPROGRAM
             #pragma target 4.5